The present invention relates to a spiral binder for papers and the like having marginal perforations and, more particularly, to a improved spiral binder having a spiral binding element.
In the past spiral ring binders have been constructed such that a narrow gauge plastic or metallic wire that has been helically or spirally coiled is passed through perforations in the margins of the papers, such that the papers are held in bound condition. The wires used in these binders are usually crimped or bent at their ends to prevent the papers from unbinding. The crimp or bend in the terminal end of the wire also acts to prevent the coils from rotating, thereby preventing the coils from gradually creeping outward at either end of the binder.
The spiral binders described above have come to be considered permanent for all practical purposes as they can not be refilled or reused without great difficulty and inconvenience to the user.
To overcome the shortcomings inherent in the devices described above, my prior patent, U.S. Pat. No. 5,417,508, disclosed a spiral-type binder having opposite coiled ends with a plurality of spiral coils interposed therebetween and a removable locking element coupled at both ends of the coil. This construction permitted the binder when in the locked state to securely retain the bound pages while at the same time permitting the removal of the locking element to add or remove pages to and from the binder.
The locking element as disclosed in my prior patent included a first end adapted to at least partially encircle one ring of the coil and a second end adapted to be inserted through a hole provided in the outermost ring of the coil.
Although the binder disclosed in the '508 patent is effective, over time it became apparent that the binder disclosed therein could be improved.
First, the binder disclosed in the '508 patent is somewhat costly to manufacture in that a molding process was used to produce the spiral binding element. As a result, a rather intricate and costly mold was required. Further, if a different length or diameter spiral was desired a new mold was required, resulting in additional costs.
Second, if the alignment of the molds used in the molding procedure is not perfect the resultant parts may have ridges or steps that may hamper the binding or unbinding of the papers held by the binder.
It is therefore, the object of the present invention to provide a spiral binder that overcomes the defects and disadvantages of the prior art.
It is another object of the present invention to provide a improved reusable spiral binder that is simple in construction, easy to operate and durable.
It is a further object to provide an improved locking device that does not compromise the structural integrity of the spiral element.
It is another object to provide a spiral binder that inexpensive, versatile and easy to manufacture.
These objects, together with other objects and advantages, will be apparent from the following disclosure of the present invention.